The new ZWO EFW-EOS adapter opens the door to using Canon EOS lenses with your monochrome ASI1600 cooled camera and EFW filter wheel.
It is a short length EOS lens to male-T2 adapter that only adds 17.5mm to the imaging train. Connected the ZWO EFWmini, the sensor of an ASI1600 is 44mm behind the bayonet fitting of your EOS lens. This allows it to reach focus.
ASI1600MM-C backfocus = 6.5mm
EFWmini backfocus = 20mm
EFW-EOS adapter backfocus = 17.5mm
Total path length = 44mm
Use any Canon EOS lens with your EFW and ASI1600MM-C
All Canon EOS lenses will reach focus with this configuration. If you have a selection of telephoto lenses these can now be used for astrophotography with a cooled monochrome camera!
In addition to prime focus imaging with a telescope you can also branch out into wide field panoramas of the night sky. Add a H-alpha filter to the EFWmini filter wheel and capture faint HII regions of the Milky Way invisible to standard un-cooled DSLRs.